Turbulence is essentially an unstable air current that moves in an unpredictable way. Most people associate it with strong storms, but the most dangerous is the clear-air turbulence, which usually occurs without any visible warning.
These types of turbulence mainly occur within or near high-altitude air currents, called jet streams. They happen when two large masses of air nearby move at different speeds. If the speed difference is significant, the atmosphere cannot withstand the tension, and turbulent patterns, like swirls in water, emerge.
This was the case on a Delta Airlines flight covering the route between Salt Lake City and Amsterdam. It was affected by strong turbulence on Wednesday night, causing injuries to 25 passengers and necessitating an emergency landing at Minneapolis - St. Paul International Airport.
The aircraft, an Airbus A330-900 with 275 passengers and 13 crew members on board, had taken off from Salt Lake City airport at 4:30 p.m. (local U.S. time). After just over two hours of flight on a journey with a total estimated duration of nine hours, it landed in Minneapolis around 7:45 p.m. (local U.S. time).
After landing, a medical team met the aircraft to assess the passengers and crew. A total of 25 passengers have been transported to local hospitals for evaluation and treatment.
Delta has issued a statement indicating that they are "working with customers to support their immediate needs." While severe injuries due to turbulence during flights are rare, scientists warn that they could become more common as climate change alters the jet stream.
According to official figures from the U.S. National Transportation Safety Board, there have been 207 serious injuries caused by turbulence since 2009. It is estimated that out of over 35 million global flights annually, approximately 5,000 turbulence incidents are "severe or greater," involving movements that can exert over 1.5 times the force of gravity on the body.